gamescript's Introduction

GScript scripting language

'GScript' (gamescript) is an interpreted (for now) statically typed programming language. It was created using the parser generator Antlr. I may potentially use it in future games which is why it's called 'gamescript'. The main purpose of this project is the study of programming language design and development.

Features

4 types: int, float, string, bool
functions, both native (defined inside gamescript), and external (callback to host)
scoped variables, name overloading and parameter overloading with a global keyword
nested functions, function scoping and overloading
statically typed variables

Missing Features

no array types
typed function returns

Code Examples

For a lot of code check testscript.txt, it contains the entire test suite with which the language is validated. Here are some smaller code examples.

Scoping Behavior

void assert(bool obj){
    if(!obj){
        print("error, assertion failed");
    }
}

int test = 0;
void testA(int test){
    assert(test == 1);
    assert(global.test == 0);

    void testB(int test){
        assert(test == 2);
        assert(global.test == 0);
    }
    testB(2);
}
testA(1);

Random function

Dice roll example making use of the external rand() function:

int roll = (rand()*6)|int;

Operator Precedence

Operator precedence and boolean logic work as expected.

[...]
assert(true);
assert(!false);
assert(true | false);
assert(!(true & false));
assert(true | false & false); //fails if 'and/or' precedence faulty

assert(1);
assert(-1+2);
assert(0.001);

Power Function

[...]
float pow(float val, int power){
    float ret = 1;
    int i = 0;
    while(i < power){
        ret = ret * val;
        i = i+1;
    }
    return ret;
}

assert(pow(4,0) - 1 < 0.001);
assert(pow(4,1) - 4 < 0.001);
assert(pow(4,2) - 16 < 0.001);
assert(pow(4,3) - 64 < 0.001);

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